dikes :: essays research papers

â€Å"When flood waters from the Mississippi River and it’s tributaries surge down the river the volume of water is physically impossible to contain. In general, there is just to much Water!!   Ã‚  Ã‚  Ã‚  Ã‚  Ã¢â‚¬Å"The â€Å"pools† behind the navigation dams have no effect in preventing or causing floods. Like a bathtub it doesn’t matter if the pools are empty or full when the floodwaters come. Within a very short time the excess water can create an over flow (Army Corps of Engineers).† What is a Flood? A flood occurs when water is poured over the land and the ground and rivers cannot cope with it (Waterlow 8). Once a basin has filled, water will overflow its rim and resume it’s downward progress. â€Å"Gravity ensures that water must drain the land into the sea (Allaby 12).† When snow melts from a divide it is joined by more snow, and it will eventually reach the low lands. Hills down below will also shed water into the same low lands and if there is enough of this it can result in a flood (Allaby 12). The Mississippi, Missouri, and Ohio drain an area of 1,243,700 square miles, this goes from the Rocky Mountains to the Canadian boarder and Pennsylvania (Allaby 13). All of this watershed result in floods each year the snow up north melts. How a Dam Affects Flooding A dam is made to make pools at least 9 ft. deep so that barge traffic can navigate freely through out the river. A lock is made so the barges can move from one pool to another (Army Corps of Engineers). The combination of these two make up a lock and dam system. Between St. Anthony Falls, MN, and Granite City, IL there are 29 lock and dam systems. It is said, in the beginning of this page in fact, that dams do not control flooding. Dams weren’t made to control floods and they never will, because floods are so unpredictable and so uncontrollable (Army Corps of Engineers). What is a Dike A dike is an embankment built to control or hold back the water of a river, stream, sea, etc. (Waterlow 25). In building a dike you can use sandbags, dirt, or both put together. You will build up a wall, getting it as compact as possible, as high as you think is needed to hold back the floodwaters. In the Netherlands farmers have used dikes to protect their farms from floods for hundreds of years (Waterlow 25).